The present invention relates to a device and program for pointing a position on the screen of a display device and a method of sensing a pointed position.
There has been developed and practically used a game system which used a pointing device such as a gun-type controller or the like for shooting target objects. In such a game system, as shown in FIG. 1A, a player 302 holds a gun-type controller 300 with one hand and aims it at a target object on the screen 312 of a display device 310. When a trigger 304 is actuated by the player 302, a position 314 on the screen 312 pointed by the gun-type controller 300 is sensed by a photosensor or the like included in the gun type controller 300. If the pointed position 314 coincides with the position of the target object displayed on the screen 312, it is judged that the shot hits the target object. If not so, it judged that the shot does not hit the target. One of such gun-type controllers is disclosed, for example, in Japanese Patent Application Laid-Open No. 10-118338.
The conventional display devices including TV receivers was mainly of the standard scan type taking NTSC mode or the like in which the number of horizontal scan lines was 525 and the number of frames per second was 60. In such a standard scan type display device, synchronous (horizontal and vertical) signals contained in a video signal coincided in timing with synchronous signals used in the display device, as shown by A1 and A2 in FIG. 1B. Therefore, if the output timing of a light detection signal from the photosensor in the gun-type controller was measured using the synchronous signals contained in the video signal. the position pointed by the gun-type controller could accurately be calculated.
On the other hand, with recent improvements of the TV receivers, a multi-density (double-, triple- or more density) scan type display device which can realize a high-fineness picture by changing the scan mode without varying the video signals themselves has been put to practical use. Such a multi-density scan type display device realizes a high-fineness picture representation equal to high-vision by interpolating scan line signals to increase the number of scan lines up to two or more times more than those of the standard scan type.
However, the multi-density scan type display device is disadvantageous in that the frequency of the synchronous signals contained in the video signal does not coincide with that of the synchronous signals used in the display device, as shown by A3 and A4 in FIG. 1C. Moreover, the synchronous signals used in the display device retard relative to the synchronous signal in the video signal, as shown by A5 and A6 in FIG. 2A. In addition, the synchronous signals used in the display device may retard by one or more frames relative to the synchronous signals contained in the video signal depending on the type of the display device since the interpolation for the scan signals is carried out using the information relating to the present and previous frames. It has been thus found that the conventional gun-type controllers could not accurately calculate the position pointed by such a multi-density scan type display device.
To overcome the aforementioned problems of the prior art, it is an objective of the present invention to provide a position pointing device, a program and a detecting method of a pointed position which can obtain accurate information of a pointed at position without depending on a scan mode.
To this end, the present invention provides a position pointing device for pointing a position on a screen of a display device, comprising: a pointer which is used to point a position on a screen of a display device; a photosensor provided in the pointer which senses a light from a position pointed by the pointer; and discriminating means which discriminates a scan mode of a display device based an the light detection signal from the photosensor.
According to the present invention, a light from a position pointed by the pointer (pointing body) is sensed by the photosensor, for example. When an operator such as a player or the like uses the pointer to point a position on a screen of a display device. Based on a light detection signal from the photosensor, the discriminating means discriminates a scan mode of the display device. If a scan mode in a display device is discriminated in such a manner, accurate information of a pointed position can be obtained without depending on a scan mode.
Other methods discriminating a scan mode based on a converting signal of a light detection signal from a photosensor without using the light detection signal directly or a method based on an equivalent of a light detection signal falls within the scope of the present invention.
The discriminating means may discriminate a scan mode of a display device by detecting a frequency component of the light detection signal.
A scan mode may be discriminated using other elements of a light detection signal (any element other than a frequency component).
The discriminating means may judge that a scan mode of a display device is not a standard scan type, but a multi-density scan type when a frequency component of the light detection signal includes a frequency component of a synchronous signal of a multi-density scan type display device.
The scan mode to be discriminated by the present invention is not limited to a standard scan type such as NTSC type and PAL type and a multi-density scan type (including double- or more density), but may include a high-vision mode.
The position pointing device may comprise position calculating means which measures a light detection timing based on the light detection signal, a count timing setting signal and a count clock signal, and calculates a position pointed by the pointer; and correcting means which corrects a count timing of a light detection timing in the position calculating means based on correcting information of the pointed position.
For example, the position calculating means may start a counting step using the count clock signal at a timing set by the count timing setting signal, measure the light detection timing and calculate the position pointed by the pointer. Then, a count timing of a light detection timing may be corrected based on the correcting information of the pointed position. Thus, for example, such a situation in which a light detection timing overlaps with a timing at which the count timing setting signal becomes active, thereby disenabling a measurement of a light detection timing can be avoided.
The correcting means may generate the count timing setting signal by shifting a timing at which a synchronous signal included in a video signal becomes active based on the correcting information, and may correct a count timing of a light detection timing in the position calculating means.
Thus, the count timing setting signal can be generated and a count timing of a light detection timing can be corrected through a simple processing.
The position pointing device may comprise position calculating means which measures a light detection timing based on the light detection signal, a count timing setting signal and a count clock signal, and calculate a position pointed by the pointer; and frequency switching means which switches a frequency of the count clock signal based on discriminating information of a scan mode obtained by the discriminating means so that a resolution in detecting a pointed position remains unchanged when a scan mode of a display device is changed.
Thus, accuracy in detection of a pointed position can be maintained without depending on a scan mode.
A computer-usable information storage medium comprise a program for causing a computer to realize: means which performs a process of causing a display device to display a scene for regulating a position pointed by a position pointing device; and means which receives discriminating information of a scan mode of a display device and calculated information of a pointed position from the position pointing device which discriminates a scan mode of a display device based on a light detection signal from a photosensor, then calculates correcting information of the pointed position and transmits the calculated correcting information to the position pointing device. A computer-usable program (including a program embodied in carrier wave) comprises a processing routine for causing a computer to realize the above described means.
According to the present invention, an operator such as a player and the like can regulate a position pointed by the position pointing device while viewing the regulation scene. Based on discriminating information and information of a pointed position from the position pointing device, correcting information of the pointed position is calculated and transmitted to the position pointing device. Thus, based on this correcting information, the position pointing device can correct a count timing of a light detection timing in the calculation of the pointed position. As a result, accurate information of a pointed position can be provided without depending on a scan mode.
A computer-usable information storage medium comprise a program for causing a computer to realize: means which performs a process of causing a display device to display a distinctive frame scene for detecting a frame lag of a light detection signal in a position pointing device; and detecting means which detects a frame lag of a light detection signal due to a scan mode of a display device, based on an output timing of a video signal on the distinctive frame scene and an output timing of pointed position information which is output from the position pointing device corresponding to the distinctive frame scene. A computer-usable program (including a program embodied in carrier wave) comprises a processing routine for causing a computer to realize the above described means.
According to the present invention, the distinctive frame scene for detecting the frame lag is displayed and the frame lag of the light detection signal is detected using the distinctive frame scene. Accurate information of a pointed position can be obtained even in a display device such that the light detection signal lags by one or more frames.
The distinctive frame scene for detecting a frame lag is ideally a whole black-colored scene, but the present invention is not limited to such a scene. For example, a frame lag may be detected by displaying a whole white-colored scene while a whole black-colored scene is displayed. In such a case, a whole white-colored scene is the distinctive frame scene for detecting a frame lag.
In the information storage medium and program, the distinctive frame scene may be a whole black-colored scene, and the detecting means may detect a frame lag of a light detection signal based an output timing of a video signal of the whole black-colored scene and an output timing of pointed position information representing that no light from a display device is detected.
Thus, a frame lag can be detected through a very simple processing of only displaying a whole black-colored scene.